Considering many F500 have old crusty mainframes deep in the bowels of their core operations… who wants to deal with that stuff. The stories I could tell from doing security consulting engagements and peering into these abysses. HN is a bubble about this stuff and loses perspective some of the time. The cool and sexy engineering might end up funneling into a harder to reach place, but meat and potatoes software maintenance and engineering that keeps big business going is not going anywhere. The things and languages we are inventing now will take decades to penetrate and replace the things deep in big business right now. Never mind the horror that is operations software like SAP.
Of course it's decreasing. The amount of people required to maintain an application of a given size continues to drop significantly over time.
Something like Docusign, once built out, could be maintained by a handful of people using serverless components. Same thing with Twitter and pretty much every other application.
Interestingly, as a side effect of this, the marginal gains on the most skilled engineers continues to increase.
For certain classes of work it is very difficult to hire even at the top of the market. There are positions my company would happily pay a million/yr to fill and simply cannot find anyone who meets the requirements.
It's hard to list all of the sorts because sometimes the needs are quite nebulous. Sometimes it's someone who's a great engineer who's just... really great at certain kinds of growth hacking, whatever that entails. These are more "you know it when you see" opportunities. Engineering leadership can be sort of similar. The kind of person who can "make things happen". More technical roles are often easier to describe. A few concrete examples:
Someone who got their PhD researching databases who is also a very experienced software engineer.
A senior software engineer who's worked for a few years in the finance world, and understands some of the more advanced math like stochastic calculus.
Someone with experience helping hypergrowth mode startups whose main DB is MySql to adopt Vitess.